The_Undersea_Murder.

Boston Blackie is a fictional character who has been on both sides of the law. As originally created by author Jack Boyle, he was a safecracker, a hardened criminal who had served time in a California prison. Prowling the underworld as a detective in adaptations for films, radio and television, the detective Boston Blackie was "an enemy to those who make him an enemy, friend to those who have no friend."
The Boston Blackie radio series, starring Chester Morris, began June 23, 1944, on NBC as a summer replacement for The Amos 'n' Andy Show. Sponsored by Rinso, the series continued until September 15 of that year. Lesley Woods appeared as Blackie's girlfriend Mary Wesley, and Harlow Wilcox was the show's announcer.

On April 11, 1945, Richard Kollmar took over the title role in a radio series syndicated by Frederic W. Ziv to Mutual and other network outlets. Over 200 episodes of this series were produced between 1944 and October 25, 1950. Other sponsors included Lifebuoy Soap, Champagne Velvet beer and R&H beer.